1. Field of the Invention
The present invention relates to multi-cylinder internal combustion engines. More particularly, the present invention relates to an improved multi-cylinder combustion engine including an oil filter, an oil cooler, and a balancer, that provides improved serviceability, oil cooling, and evenly-distributed oil pressure.
2. Description of the Background Art
A number of different designs are known for multi-cylinder internal combustion engines. Many of the known engine designs include an oil filter, an oil cooler, and a balancer.
In a conventional multi-cylinder internal combustion engine, the oil filter is attached to a front surface of the internal combustion engine, with the axis of a cylindrical case thereof directed in the front-rear direction, together with an oil cooler (see, for example, Japanese Laid-open Patent No. 2001-227317 (FIGS. 2 and 5) & Japanese Laid-open Patent No. Hei 8-232626 (FIG. 6)). During replacement of the oil filter element in this arrangement, the case of the oil filter is attached and detached in the axial direction of the cylindrical case, namely, in the front-rear direction. In the known multi-cylinder internal combustion engine, however, since a number of exhaust pipes according to the number of cylinders are aligned at a front surface of the internal combustion engine, the oil filter case can be difficult to remove and replace, because of interference by the exhaust pipes.
There have been known engine designs in which an oil cooler is disposed at a substantially central portion in the left-right direction of a front surface of an internal combustion engine (see, for example, Japanese Patent Laid-open No. 2001-227317 (FIGS. 2 and 5) and Japanese Patent Laid-open No. Hei 8-232626 (FIG. 6)). In addition, there has also been a known engine design in which a balancer is disposed at a substantially central portion in the left-right direction of a front surface of an internal combustion engine (Japanese Patent Laid-open No. Hei 6-193681 (FIG. 2).
However, there has not been a known engine design in which both the oil cooler and the balancer are disposed, in close proximity to one another, at a substantially central portion of the front surface of the internal combustion engine.
Ordinarily, where either the oil cooler or the balancer is disposed at a central portion of the front surface of the internal combustion engine, the other is disposed at a rear or a lower portion of the internal combustion engine.
Although the known engine designs have utility for their intended purposes, a need still exists in the art for an improved design for a multi-cylinder combustion engine with an oil filter, an oil cooler, and a balancer. In particular, there is a need for an improved design for a multi-cylinder combustion engine with an oil filter, oil cooler, and a balancer that improves engine serviceability, and enhances oil cooling.